"`from langchain.chat_models import ChatOpenAI`"
        )
        return values
    @property
    def _default_params(self) -> Dict[str, Any]:
        """Get the default parameters for calling OpenAI API."""
        return self.model_kwargs
    def _get_chat_params(
        self, prompts: List[str], stop: Optional[List[str]] = None
    ) -> Tuple:
        if len(prompts) > 1:
            raise ValueError(
                f"OpenAIChat currently only supports single prompt, got {prompts}"
            )
        messages = self.prefix_messages + [{"role": "user", "content": prompts[0]}]
        params: Dict[str, Any] = {**{"model": self.model_name}, **self._default_params}
        if stop is not None:
            if "stop" in params:
                raise ValueError("`stop` found in both the input and default params.")
            params["stop"] = stop
        if params.get("max_tokens") == -1:
            # for ChatGPT api, omitting max_tokens is equivalent to having no limit
            del params["max_tokens"]
        return messages, params
    def _generate(
        self, prompts: List[str], stop: Optional[List[str]] = None
    ) -> LLMResult:
        messages, params = self._get_chat_params(prompts, stop)
        if self.streaming:
            response = ""
            params["stream"] = True
            for stream_resp in completion_with_retry(self, messages=messages, **params):
                token = stream_resp["choices"][0]["delta"].get("content", "")
                response += token
                self.callback_manager.on_llm_new_token(
                    token,
                    verbose=self.verbose,
                )
            return LLMResult(